Using the alternate data entry page, you can choose
to have certain words not show up in the word list.

This feature can be used in a couple of ways:

Bonus words.
If you want to add extra words to see if people
can find them, you can click the check box next to the extra words.
These words don't show up in the word list to prompt the people
working the puzzle. Think of a list of names of students in a class,
with the teacher's name as a bonus word.

Distractor words.
If you want to be devious, you can add all of your normal words,
and then add mis-spellings of words as extra words. These words
also don't show up in the word list. But it might snag a person
who is moving through the puzzle (too) quickly.

If you are generating answer keys, then for the first case it is reasonable
to mark these bonus words as real words. However, for the second case, they
really aren't words and you don't want to have these words in the answer key.

This option allows you to make a choice if the extra words are omitted from
the answer key or not.